This invention is related to the field of biochemical sensors using integrated circuits. The sensors are specifically designed to be biocompatible for implantation in the human or an animal body, but may also be used in laboratory or industrial settings. The sensor communicates to either or both of a pump actuator, and to an externally located RF transmitter/receiver.
Diabetes mellitus is a disease in which glucose levels in the patient""s blood become out of balance and largely unregulated and is the leading cause of morbidity in the United States. Studies have shown that when glucose levels are tightly maintained, induced secondary pathological states such as peripheral vasculopathy, which leads to such conditions as diabetic retinopathy, neuropathy, nephropathy and amputation of extremities, are largely avoided. The level of glucose control required to inhibit these associated pathological states is typically beyond the ability of diabetic patients to regulate in their own homes. Diabetic patients are required to prick a finger multiple times a day, draw a small sample of blood, place it in a glucose sensor, and then administer themselves an appropriate injection of insulin. Patient compliance is clearly an issue. If a patient does not accurately dose their insulin levels to correspond with glucose levels, then this level of insulin therapy is insufficient to stop the progress of the above mentioned pathological conditions.
A major step forward in the fight against diabetes would be the ability to automatically monitor blood glucose levels using one or more embedded sensors which eliminate the need for frequent finger pricks. After the glucose levels were automatically sensed, the sensor should be smart enough to determine if the levels were outside a preset range. The sensor would then either send a message to the patient that their glucose levels were out of range, or in the preferred case, activate an implanted insulin pump to automatically maintain glucose levels within physiological levels.
The disclosed sensing architecture describes a device, and outlines the fabrication process of the device to make a wireless glucose sensor. Such a sensor is ideal for implantation within the human body for the control of diabetes mellitus. However, it could also be used in biotech processing plants where glucose levels are required to be maintained within a certain range, or in the veterinary market for the treatment of animals that have diabetes. Because this sensor is based on semiconductor technology, the preferred embodiment is to automatically actuate a pump to meter an appropriate dosage of insulin or to add additional glucose if levels rose above or fell below a programmable range. The disclosed sensor architecture specifically deals only with the sensor. The connection of how this sensor may interact with a pump is described in a previously submitted U.S. patent application Ser. No. 09/521,922 by Ishikawa et al., entitled xe2x80x9cImplantable Drug Delivery Systems,xe2x80x9d filed Mar. 9, 2000, and which is hereby incorporated by reference. The sampling frequency of the glucose sensor is programmable, and is determined by the radio frequency (RF) transmitter/receiver, which is external to the sensor. In the case of implantation in the human body, the external transmitter/receiver is worn by the patient, and is ideally similar in size and appearance to a beeper or other socially acceptable device. In the case that there is no pump available, or if the pump requires maintenance, this external transmitter/receiver can be programmed to sound an audible alarm or series of various alarms. The patient would then be able to manually administer an appropriate dosage. This constant feedback to the patient would allow a much tighter control of blood glucose levels, and could potentially result in a substantial decrease in mortality and morbidity currently associated with diabetes.
The disclosed sensor system is valid for a variety of biological molecules. In particular, any biological molecule that undergoes enzymatic oxidation with the concomitant production of an acid and/or hydrogen peroxide can be detected by one or more of the disclosed embodiments as described herein. Detailed discussion focuses on glucose, for example, but it should be kept in mind that glucose is only one specific example of the multitude of applications.
The present invention disclosed and claimed herein, in one aspect thereof, comprises a biochemical sensor fabricated on a ball integrated circuit. A sensor media is mounted to the ball integrated circuit, the sensor media operable for sensing biochemical molecules. An onboard communication link transmits data sensed by the sensor media from the ball integrated circuit.